Indoor office air is an important source of worker exposure to the potentially toxic substances known as PFCs, or polyfluorinated compounds, according to a new study.

''Workers who spend their day in a typical office environment are likely to have exposure to PFCs through the air, and that seems to lead to PFC levels in their blood," says researcher Michael McClean, ScD, associate professor of environmental health at the Boston University School of Public Health.

PFCs are widespread in the environment, often found in and given off by consumer items such as furniture, carpet stain repellents, paint, and food packaging. More than 95% of people in the U.S. have been found to have some levels of the chemicals in their blood.

In recent years, research has focused on potential health hazards linked with the chemicals. Some research has linked exposure to lower birth weight and to higher cholesterol, for instance.

The Boston researchers wanted to find out where the common sources are, and decided to investigate the exposure to the chemicals in typical offices.

The study is published in Environmental Science & Technology.It was funded by the National Institute of Environmental Health Sciences.

PFCs in the Office: Study Details

During the winter of 2009, McClean and his colleagues sampled the air in 31 Boston offices for four days. After that, they took a blood sample from each of the 31 workers. The researchers wanted to see if the PFCs in the air correlated with the PFCs found in the workers' blood.

Workers had to be in the office at least 18 hours a week to participate, McClean says.

The researchers analyzed the air samples for many PFCs, including fluorotelomer alcohols (FTOHs), sulfonamides (FOSAs), and sulfonamidoethanols (FOSEs).

They analyzed blood samples for 12 PFCs, including PFOA (perfluorooctanoate) and PFOS (perfluorooctane sulfonate), two very common PFCs.

"Most of our participants came from two buildings," McClean says. One was relatively new, the other building older but with some new carpeting.

The FTOHs were highest in the air samples. The researchers found that concentrations of FTOH were three to five times higher than levels reported in prior studies of household air.